Control system



Nav. 30, 1943.l P. s. DlcKEY.

CONTROL SYSTEM original Filed Das.A 18, 1935 5 Sheets-Sheet 1 kvk 3:56

Nw. 3o, 1943 P. s. -mcKEY 2,335,655

coNTRoL SYSTEM l lOriginal Filed Dec. 18, 1935 3 Sheets-Sheet 2v INVENTOR @40A S. D/c/rfy Nov. 30,1943. P. s. DlcKr-:Y

CONTROL SYSTEM original Filed Dec. 1'8, 1955 s sheets-snaai :s

INVENTOR PAUL @1c/ffy BY 1 ATTO Y Patented Nov. 30,1943

Es' PATENr OFFICE coN'rltoL sYs'rEM Paul S. Dickey, Cleveland, Ohio, assigner to Bailey MetervGompany, a corporation of Delaware Original application December 18, 1935, Serial No. 55,023. Divided and this application May 5, 1938, Serial'No. 206.304

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Claims.

s This invention relates toa method and means for operating and controlling the operation of vapor generators; particularly vapor generators of the drumless, forced flow type, having a liuid flow path including/one or morelong smallbore tubes, in which the ow in the path is initiated by the entrance of liquid under pressure at one end, andthe .exit of vapor only at the other end; characterized by an inflow of liquid normally greater than the outiiow of vapor, the difference being diverted from the path intermediate the ends thereof, Vas disclosed and .claimed in my parent Patent 2,170,346, issuedA August 22, 1939, of which this application is a division. Y

The principal object of this invention relates to a kindling and igniting control system for this type` of vapor generator.

Still another object is to provide a sequenceV and protective system for maximum safety of operation.

Further objects will become evident from a study of the specification and ofthe drawings, in which:

Fig. 1 diagrammatically illustrates a. drumless forced flow vapor generator, combined with the requisite apparatus to control the functioning thereof, and such apparatus shown in partially diagrammatic fashion. Y

Fig. 2 is a wiring diagram related particularly to the layout of Fig. 1.' Y. y

Fig. 3 illustrates a thermostatic relay.

Fig. 4 is a partial-section, in" the direction of the arrows, along the-lines I`4 of 3. s

Fig. 5 is an elevation of a ilame responsive device.

Fig. 6 is a sectional elevation of Fig. 5 along 'the' line 6-'6 in the direction of the arrows. f

In thev various drawings, identical parts bear the same reference numerals. Referring now to Fig. 1, I show an arrangement wherein I actually measure the vapor outflow through the .pipe 244 to a turbine or other utilizer. To this end, I provide a now meter- I8 connectedto the pipe 2 across an orifice.

or other restriction 19. Theow meter is adapt- 'ed to vertically position a pilot stem 42 ,relative positioning a set of dampers 83. 83 are preferably so located relative tothe fluid path through the vapor vgenerator as to control the relative heating of different portions of the uid path, and thus control the vapor outflow temperature.

In Fig. 2 I illustrate the wiring circuit, particularly in connection with the arrangement of Fig. 1. The relative location and arrangement ofthe mechanical -pieces of apparatus is the same on the two gures. For example, the Bourdon tubes I9 and 22, as well as 'the level indicator 29; the valve I0, the valve l1, the pipe 5, and the .shaft of the auxiliary turbine areat the same relative locations on Fig. 2 as on Fig. 1.

What may be termed a master switch is shown at X and a second'switch at Y. In connection with the pressure responsive Bourdon tube I9 I provide a high pressure trip HP and in connection with the temperature sensitive Bourdon tube 22 I provide a high temperature trip HTi In connection with the level responsive device 29 a low level trip LLlis provided and for each of the ve tubes leading into the separator drum 232 there is a double contact switch HF actuated upon abnormal temperature within the particular vtube with which it is connected. `A- signal light O is Aprovided with eachl of the trips HF which lights upon the occurrence 'of abnormal temperature. At" LO is a pressure responsive trip actuated to open two circuits uponl abnormal low :lubricating oil pressure of the auxiliary turbine shaft. At LW is a switch actuated to open two circuits upon abnormally low water pressure at the inlet .tothe valve I1. C

At B I indicate a spark Plug or similar device located adjacent the gas burner-'8 (Fig. 1) for' kindling the iire.

Assuming the unit-is not operating and it is after'four seconds'and energize E which then to a -pilot casing 43 to vary, an air loading pressure eective Aupon the relay l'l'proportional to' the rate of vapor outflow.

The Bourdon tube 22 positioned responsive -to variations' in vapor outflow temperature, -isadapted to vertically position a pilot stem 80 for varyingV an air loading pressure through the lconnection 8| upon a pneumatic actuator 82 for opens the fuel-oil valve J inthe 'pipe 5, closes cil by-pass 'valve M, and opens the coil circuit of F. After four seconds F drops out, energizing A (if the name is established so that the llame failure off the valve I0, drops out C and closes anothercircuit to the coil of E. When C drops out, E is The dampers energized so that the by-pass of D (to the coil of E) is opened.

A failure of flame at the burner I causes G to drop out, deenergizing A which starts the ignition, and D which turns on the valve III, energizes C, and drops out E. :As E drops out, the fuel oil valve J is closed, M is opened, land F energized. The cycle continues as outlined the closing of switch X.

If HT, HP, or BF trip out, then E is dropped out closing J, openingM, and energizing F. Then the above mentioned flame failure cycle is followed except that the ignition and gas valve IIIA are kept on and E cannot pick up until the particular trip (HF or HP or HT) is closed, due to correcting ofthe out-of-limit condition.

There is a current flow through the heating element of I whenever C and E are energized,

which condition exists when the fuel oil is on and the lame failure detector U has not energized relay G. Thus if the flame is not established at the burner 4 Within ten seconds after E is energized, T trips, shutting of! S, K, and J. P will also trip after about ve consecutive relighting cycles.

In the event of low water pressure to the inlet of the feed pump at LW, or low lubricating oil pressure at LO to the auxiliary set, the ignition S, valve K, and valve J, are shut off by LW or LO.

In addition these tripsdeenergize the solenoid P, which in turn trips the auxiliary turbine valve operator thus stopping the auxiliary set. 'Ihe solenoid P normally holds the valve I I'I (which is located in the air line S8) in a condition for free passage of air control pressure from 4I to 40. When P is deenergized, the valve II'I closes oil' connection with the'stabilizing relay 4I and opens the diaphragm chamber of the actuator 40 to atmosphere, thusgallowing the spring loading of such actuator to position the actuator toits closed position. This trips the auxiliary turbine oil'.

By the switch X the complete system may be shut down. By the switch Y the auxiliary turbine itself may be tripped out.

A solenoid actuated valve L is located in the air supply lineleading to theY pilot valve of the pressure sensitive Bourdon tube I9. Referring to the wiring diagram of Fig. `2, it will be observed that L 'ls normally energized holding its valve open.

When any of the safety switches trip out andopen the electrical circuit to L, the valve closes, thus shutting off the supply of air to the pilot and releasing air pressure from the'air pressure pipe 10. The spring loaded valve I8 in theby-pass line around the water pump then closes, as does the damperl I at the inletto the air blower.

Such operation is particularly desirable upon excessive temperature actuating .l any of the control tends to immediately relight the burner and the blower may still be operating at a high rating.

' The solenoid actuated valve L might equally as well be inserted in the air pressure line 1I), in which case when deenergized the valve would i close off from the pilot 59 and open, to the atabove following mosphere, thediaphragm actuator I8 and the actuator 38.

"at L' of Fig. 1, I indicate a solenoid actuated valve in the air supply line to the pilot I2 of the fuel-air ratio control. This valve is similar in function to the valve L and in the wiring diagram of Fig; 2 may replace, in the electrical circuit, the valve L. It may be connected in parallel with the valve L in the wiring circuit if both valve L and L are used.- It iselective in closing the fuel supplyvalve i3.

Referring to Fig. l, the secondary control of fuel supply is by the?v regulating valve I3 from fuel-air ratio. If air flow varies, the fuel supply varies proportionately. I have provided a solenoid operated valve M in a by-pass around the fuel pump 290, regulating valve i3, and meter I d.. '.Ihis solenoid is electrically in parallel with the solenoid of valve J, so that when J is tripped out and closes the by-pass, valve M automatically opens, thus by-passing oil during that part of the lighting cycle when the main solenoid valve J is closed. If ilamefails the valve J closes, which shuts off the supply of fuel to the burner. Ii' I did not provide the by-pass and vvalve M there would then be a tendency for the meter I4 to decrease to zero and the fuel-air ratio would open the regulating valve I3 wide. If then the recycling opened the valve J there would be a wide open valve I3 which would immediately send a heavy volume of oil through J to the burner far in excess of what was desired. By providing the by-pass and valve M, then when the fire goes ,out and J is closed, the valve M opens and the switches HF, for such trip-out will close the fuel valve J, and it is desirable that the air damper i5 be closed at the same time. The auxiliary set may continue to operate, thus driving the air blower and the only way that air iiow to the iurnace can be decreased' is by shutting oil' the i damper I 5. Atvthe same time it is desirable to close the by-pass valve I8 to insure that all of the water being pumped by the water pump goes to the vapor generator to protect against burning when :dame fails because the recycling ignition ilow through the meter I4 is maintained approximately as it was before in ratio with the air but the oil is now by-passing back through the valve M. The vvalve I3 does not open excessively or materially further than it was before and thus the flow available at J when J next opensis not excessive.

Referring particularly to Fig. 1, it is sometimes desirable to maintain the level within the separator 232 variable (directly or inversely) with rating. This may be accomplished through relative adjustment of the range and sensitivity of' the control from the steam outflow meter 'I8 (representative of rating) and of the level recorder 29. Such adjustment will allow of control tending to maintain the `level within the separator at a predetermined value,` or at a level increasing -with rating or at a level decreasing with rating in desired manner; l

At Figs. 3 and 4- I show an assembly of a ternperature switch HF. In preferred construction a quartz rod II8 and its encasing metal tube IIS are located in or adjacent -to one of the tubes as, for example, 20B just before it enters the separator 232. The encasing tube I I9 is fastened in an insulating member |20, While the quartz rod IIB is slidable therethrough. A secondinsulating member I2I is pivotally fastened to the quartz rod and the member I20.-

When subjectedv to a temperature below a predetermined high value, the relative location of parts is as shown in Fig. 4 wherein contact is c.....,..i between wires |22 and |23 and opened beis spring urged away from tween wires |24 and |25. As temperature increases the metallic tube ||9 elongates to the leftv from the member |20, carrying with it the quartz rod ||8 which has relatively no variation in length with temperature. Such motion of the quartz rod to the left moves the member |2| around the contact 22, |23 as a pivot and against the compression of the spring |26 until at a certain degree of motion the contacts |24, |25 are closed, thus lighting the signal light O. If further increase in temperature occurs, then at a predetermined temperature further expansion of the tube ||S causes the member 2| to pivot around the contact |24, |25 open-circuiting the contacts |22, |23 and tripping-,olf the unit.

At Figs. 5 and 6 I illustrate a preferred construction of the device U, which I term a ame failure detector. A photronic cell |29 is located to look at the flame from the burner 4 and generates a `current in the wires |21, |28 effective to energize the relay G When flame is present in.

the furnace. Between the photronic cell |29 and the flame is located a water cell or screen provided with a thermal circulation system Certain featuresof the wiring diagram, ignition and flame failure circuits, temperature switch HF, and flame failure detector U, are disclosed and claimed in the co-pending application of Jack F. Shannon, Serial No. 55,028, filed Decem ber 18, 1935.

While I have chosen to illustrate and describe certain preferred embodiments of my invention,- it is to be understood that this is by way of illustration only and that I am not tobe limited thereby except as to the claims in view of prior art.

What I claim as new, and desire to secure by Letters Patent of the United States, is:

1. A kindlingand igniting control system for a vapor generator receiving a fluid in the liquid state and delivering'the uid in a vapor state, said control system comprising means responsive to the value of a variable condition of the fluid adapted to close off the fuel supply whenv said variable condition reaches a predetermined value, normally inoperative kindling and igniting means for the fuel supply, means for `rendering said fuel kindling and igniting means operative when said condition reaches said predetermined value, means for maintaining said kindling and igniting means operative for a predetermined time duration after said condition reaches said prede- -termined value andrendering said kindling and igniting means inoperative if said condition continues at said predetermined value thereafter. means for reestablishing the fuel supply and rendering operative `said kindling and igniting means when said variable condition falls below said predetermined value, and means rendering said kindling and igniting means inoperative after ignition of the fuel.

2. A kindling and igniting control system for a vapor generator receiving a fluid in the liquid state and delivering the fluid in a vapor state, said control system comprising in combination therewith of, means responsive to the value 0f a vvariable condition of the fluid adapted to close oif the fuel supply when said variable'condition reaches a predetermined value, normally in- A operative kindling and igniting means for the igniting means inoperative if said condition continues at said predetermined value thereafter, means for reestablishing said fuel after said variable condition has fallen below said predetermined value and said kindling and igniting means has been operating a predetermined length of time, and means rendering said kindling and igniting means inoperative after ignition of the fuel.

3. A kindling and ,igniting control system for a vapor generator receiving a uid in theliquid state and delivering the fluid'in a vapor state, said control system comprising means responsive to the value of a variable condition of the fluid adapted to close off the fuel supply when said condition reaches a predetermined value,

after said Ivariable condition has fallen below` said predetermined value, and means for closing oi! said fuel supply if said fuel fails to ignite.

4. A kindling and igniting control system for a vapor generator heated by products of combustion, said control system comprising, means rer/5" Sponsive to a variable in the operation of said' vapor generator controlling the supply of the elements of combustion thereto, igniting means for said elements of combustion and kindling means for said igniting means rendered operative upon said variable reaching a predetermined value, and current generating means responsive 'to the light of a flame established by said elements of combustion, the current generated by said light responsive means energizing a relay circuit and thus rendering said igniting and kindling means inoperative.

5. Akindling and igniting control system for a vapor generator heated by products of combustion, said control system comprising, means responsive to a variable in the operation of thel vapor generator controlling the supply of the elements of combustionthereto, kindlingmeans and igniting means for said elements of combustion rendered operative upon said variable condition reaching a predetermined value, means for maintaining said kindling and igniting means operative a predetermined time interval during the existence of said predetermined value of said variable condition, and current generating means sensitive to the light of a flame established by said elements of combustion, the current generated bysaid light responsive means energizing a. relay circuit and thus rendering said igniting and kindling means inoperative.

' PAUL S. DICKEY. 

